International Publication No. WO2013/183665 discloses a contactless power supply transformer that includes a pair of magnetic pole portions, and an inter-magnetic-pole core portion provided between the pair of magnetic pole portions. The inter-magnetic-pole core portion is formed by alternately disposing a ferrite member and a thermal conductor. Heat generated due to iron loss of the inter-magnetic-pole core portion can be dissipated to the outside through the thermal conductors.